NON RAS ONCOGENES IN CHEMICALLY INDUCED RAT LIVER TUMORS

肝细胞癌是人类的主要肿瘤之一。 大鼠提供了一个最好的表征模型系统， 检查化学诱导的肝细胞的发育 carcinoma. 尽管在隔离和 在许多其他的细胞中表征活化的原癌基因 系统，有相对较少的此类报告肝 肿瘤，特别是大鼠。 甲基（乙酰氧基甲基） 亚硝基胺（DMN-OAc）是一种“条件性”肝致癌物 只有当注射到动物体内， 活跃的肝脏再生 我们已经检查了8个 DMN-OAc诱导的大鼠原发性肿瘤的转化能力 转染入NIH 3 T3细胞后， 8例原发性肿瘤中有7例 我们检测到了转化活动 形态学上 转化的NIH 3 T3细胞在软琼脂中生长，而那些转化的细胞在软琼脂中生长 在接种到裸鼠中后，测试的是致瘤性的。 由于我们以前已经描述了几种表达的特征， 原癌基因在大鼠肝脏再生生长过程中，我们 检查来自NIH 3 T3转化体的DNA的改变的ras（N- ras、rasH或rasR）、myc、erbA、erb、V-raf、A-raf或neu基因，以及 没有发现这些基因参与的证据。 初步的限制性内切酶敏感性曲线 原始DNA表明，至少有3个 在我们所处的肿瘤组中激活的独特基因在我们所处的肿瘤组中激活的独特基因 检查 该研究项目的主要重点将是 通过分子克隆分离这些基因中的每一个， 描述基因在两种正常组织中的表达， 大鼠组织和DMN-OAc诱导过程中 致癌作用 对这些基因的进一步研究将 包括将基因转染到大鼠肝“卵圆”细胞系中 并转化为具有增强的增殖能力的肝细胞。 在 在项目的后期阶段，我们将表达蛋白质， 使用杆状病毒表达系统的这些基因的产物 并描述癌基因蛋白质在细胞内 以及通过免疫荧光进行组织定位。 最终我们 希望能确定这些原癌基因在正常人和正常人中的作用。 大鼠的发育和肝细胞癌的发展。

Hepatic cell carcinoma is one of the major tumors of man. The rat offers one of the best characterized model systems for examining the development of chemically-induced hepatic cell carcinoma. Despite the rapid advances in isolating and characterizing activated proto-oncogenes in a number of other systems, there have been relatively few such reports of hepatic tumors, particularly in the rat. Methyl (acetoxymethyl) nitrosasmine (DMN-OAc) is a "conditional" liver carcinogen producing tumors only when injected into animals undergoing active liver regeneration. We have enxamined DNA from 8 primary rat tumors induced by DMN-OAc for transforming ability upon transfection into NIH3T3 cells. In 7 of the 8 primary tumors we have detected transforming activity. The morphologically transformed NIH3T3 cells grow in soft agar and those which have been tested are tumorigenic upon inoculation into nude mice. Since we have previously characterized the expression of several proto-oncogenes during regenerative growth in rat liver, we examined DNA from the NIH3T3 transformants for altered ras (N- ras, rasH or rasR), myc, erbA, erb, V-raf, A-raf or neu genes and have found no evidence for any involvement of these genes. Preliminary restriction endonuclease sensitivity profiles of the primary transformant DNA suggest that there are at least 3 dinstinct genes activated whithin the set of tumors we are examining. The major focus of this research project will be to isolate each of these genes by molecular cloning and to characterize the genes with respect to expression in both normal rat tissues and during the course of DMN-OAc induced carcinogenesis. Further studies characterizing these genes will include transfection of the genes into rat liver "oval" cell lines and into hepatocytes with enhanced proliferative capability. In the later stages of the project we will express the protein products of these genes using the baculovirus expression system and characterize the oncogene proteins with respect to cellular and tissue localization by immunofluorescence. Ultimately we hope to define the role of these proto-oncogenes in both normal rat development and the development of hepatic cell carcinoma.